PROJECT SUMMARY Contrary to the belief that the practice of tobacco smoking by waterpipes (`hookah?) is less harmful than smoking combustion cigarettes, the health risks of waterpipe smoking (WPS) may be even greater than smoking cigarettes. The risks of WPS include adverse cardiovascular and pulmonary effects. Many of the compounds in WPS impact the cardiovascular and respiratory systems: Elevated heart rate and blood pressure has been linked to nicotine and the increased carbon monoxide concentrations measured in WPS. Also, WPS generates destructive reactive oxygen species or depletes SH-containing antioxidants. Irreversible oxidative stress-induced damage of the lung epithelium may occur and has been linked to the pathogenesis of coronary artery disease and obstructive pulmonary disease. Our overall objective is to determine how changes in WPS components and smoking patterns effect the chemical composition of both the gaseous and size-resolved particulate constituents and their role in the development and exacerbation of cardiopulmonary diseases. We will specifically examine the role of inflammation and oxidative stress as mechanisms of action in tobacco smoke-related disease pathogenesis. We will use a combination of in vitro tests and in-vivo inhalation exposures with a genetically modified mouse model to quantify adverse effects on the cardiopulmonary system to specific toxicants present in WPS. Our overarching hypothesis is that exposure to hookah smoking will be associated with inflammation and oxidative stress that will induce or exacerbate cardiopulmonary responses in our in vivo mice model. We further hypothesize that these associations will be due to semi-volatile WPS components with high inflammation and oxidative potential and that removal of these compounds will mitigate the adverse effects. We will test our hypotheses with the following three aims: 1. Use state-of-the-art high resolution analytical methods to generate, sample, and quantify potentially harmful constituents in WPS to a degree that was not possible in earlier studies. 2. Assess the redox & electrophilic properties of gas- and particle-phase components present in WPS extracts using in vitro systems that explore several potentially important mechanisms of action. 3. Assess and compare cardiopulmonary toxicities of hookah smoke in mice in acute and chronic exposures with an emphasis on defining the role of inflammation and oxidative stress in lung, brain and cardiovascular systems using a sensitive, atherosclerosis-prone animal model. This will be among the first studies to evaluate differential cardiopulmonary toxicities of chemically characterized hookah smoke by in vitro and in vivo assays. The study will employ innovative state of the art telemetry to measure changes in respiration, electrocardiographic patterns and cardiac function during and after sub-chronic and chronic exposures in mice that are genetically susceptible to atherosclerosis.